The subject of the present invention is an assembly for a railway vehicle, of the type comprising a first chassis and a second chassis which is connected to the stationary chassis to tilt laterally with respect thereto on each side of a position of rest, the assembly further comprising means for moving the second chassis laterally.
The invention applies, for example, to a power pick-up assembly for a tilting railway vehicle.
Such a railway vehicle is designed so that its body shall adopt a lateral inclination with respect to the axis of the axles of its bogies in the curved parts of railway lines.
In the case of a power pick-up assembly, the first chassis is a stationary chassis intended for mounting the assembly on the roof of a railway vehicle, and the second chassis is a mobile chassis which carries a pantograph belonging to the power pick-up assembly.
If such an assembly is mounted on top of the railway vehicle for picking up power from an overhead power line, it then becomes necessary for the pantograph to be inclined laterally with respect to the body in the opposite direction to the direction in which the body is inclined with respect to its axles, so as to limit the lateral movement of the collector bow of the pantograph with respect to the contact line of the overhead power lines.
This is because if there were no such inclination of the pantograph in the opposite direction, known as tilt compensation inclination, the relative movement of the collector bow with respect to the contact line could be great enough for the line to be in contact only with the insulated parts of the collector bow or even spaced laterally from it, and this could cause damage to the overhead line and to the pantograph, particularly as the body returns to its position of rest.
Document EP-A-785,100 describes a power pick-up assembly of the aforementioned type in which the mobile pantograph support chassis is connected by four link rods to the stationary chassis. At rest, that is to say when there is no tilt compensation, the points of articulation of the link rods transversely form a downwards-converging trapezium. The lateral movement of the mobile chassis causes the pantograph to be inclined laterally with respect to the body.
The lateral movement of the mobile chassis is brought about by means of one or more rams which thrust the mobile chassis laterally and which is or are arranged on one side or both sides of the pantograph support. A control system steers the ram(s) to move the mobile chassis and provide the pantograph with tilt compensation.
To ensure satisfactory movement of the mobile chassis while at the same time limiting the unwanted movements in translation and rotation, it is appropriate to provide guides against which the mobile chassis slides, and to fit a central lateral ram on each side of the mobile chassis.
The electrical isolation of the pantograph from the roof of a railway vehicle is provided by electrical insulators arranged between the pantograph and the mobile chassis.
Correct operation of the power pick-up assembly therefore entails a complex bulky structure which is subject to dissipation of mechanical energy by rubbing at the guides which thus constitute wearing parts.
The substantial bulk of a power pick-up assembly of this kind is a particular hindrance in complying with size requirements imposed on railway vehicles without limiting the headroom available for the passengers within the vehicle.
One object of the invention is to provide an assembly of the aforementioned type which is of smaller bulk.
To this end, the subject of the invention is an assembly of the aforementioned type, characterized in that the movement means comprise an arm for driving the second chassis laterally, which arm is mounted so that it can pivot about a longitudinal axis.
According to particular embodiments, the assembly may comprise one or more of the following characteristics, taken in isolation or in any technically feasible combination:
the driving arm is connected to the second chassis at a point which roughly describes an arc of a circle centred on the said longitudinal axis when the second chassis tilts with respect to the first chassis in the vicinity of its position of rest;
the second chassis is connected to the first chassis by at least two laterally-spaced pivoting links;
the arm for driving the second chassis laterally is connected to this second chassis at a point located laterally roughly mid-way between the two pivoting links when the second chassis is in the position of rest;
each pivoting link comprises a tilting rigid support articulated, on the one hand, to the first chassis at two longitudinally-spaced points and, on the other hand, to the second chassis at two longitudinally-spaced points;
each tilting support comprises a yoke articulated by its branches to the first chassis, and two clevis mounts which extend the base of the yoke and which are articulated to the second chassis;
each tilting support has a transverse profile with its concave aspect facing towards the inside of the assembly;
the clevis mounts of each tilting support are roughly orthogonal to the branches of the corresponding yoke;
the points by which the tilting supports are articulated to the first and second chassis form, transversely, when the second chassis is in the position of rest, a trapezium which converges, in the direction from the said longitudinal axis towards a point on the second chassis to which the driving arm is connected;
the driving arm is connected to the second chassis as a pivoting and sliding link;
the assembly is a power pick-up assembly for a railway vehicle, comprising a pantograph and a pantograph support, the pantograph support comprising the first chassis for mounting the assembly on the roof of a railway vehicle, and the second chassis which carries the pantograph;
the pivoting arm is connected to the second chassis at a point located below the said longitudinal axis when the power pick-up assembly is mounted on the roof of a railway vehicle;
the first chassis comprises means for electrically isolating the pantograph from the roof of a railway vehicle on which the assembly is intended to be mounted;
the first chassis comprises electric insulators which form feet for supporting the first chassis on the roof of a railway vehicle;
the first chassis comprises four electric insulators forming support feet arranged in a square or rectangular overall configuration;
the means for moving the second chassis comprise some of the means of electric isolation;
the means for moving the second chassis comprise a rotary motor for actuating the arm for driving the second chassis, and the output shaft of the rotary motor is oriented longitudinally;
the rotary motor is connected to the driving arm by an electric insulator.
A further subject of the invention is a railway vehicle characterized in that it comprises an assembly as defined hereinabove.